They discovered that people with dyslexia find it difficult to distinguish sights and sounds that occur quickly one after the other.

"For the first time, there is evidence that dyslexia is a multi-sensory disorder," said Wallace. "It isn't solely a problem with visual processing or with language. This is a novel way of looking at the disorder.

"Until now, experts have thought that dyslexia was either a visual processing problem or a problem involving language areas of the brain. But our study suggests that it's actually a problem combining visual information with auditory information."

The researchers looked at 36 people with dyslexia and 29 without dyslexia, then studied how they responded to two lights flashing. People in the study had to tell whether the light on the left or right flashed first. A loud sound just before the flashes also helped to discriminate between the lights.

Sounds made more than 150 milliseconds before the flashes benefited all the people in the study. But sounds made up to 350 milliseconds before the flashes only helped those with dyslexia.

The researchers said that this provided evidence that the brain blurred things that happened in quick succession, and that in people with dyslexia this blurring happened over longer periods of time.

"Dyslexics were getting an advantage from sounds that were too long ago for people without dyslexia," Dr Tim Bates, from Australia's Macquarie Centre for Cognitive Science told ABC Science Online.

"There's been research on how people with dyslexia have trouble processing rapid visual information and comparable auditory problems," said Castles. "They've put those together and said the problem is to do with integrating both sight and sound. The good thing about it is that they've then linked that to how a child might be trying to learn to read."

Wallace's colleague Dr Lyn Flowers suggested that the study could be developed as a test for early diagnosis of dyslexia.

"The study did not use letters and speech sounds, suggesting that there may be a very basic sensory integration deficit in dyslexia that underlies reading difficulties," Flowers said.

Bates and Castles disagreed.

"There's no evidence for it having implications for early diagnosis," said Bates. "What may be true for some people with dyslexia, is probably not true for all people."

Castles added that more work would be needed to see if the research could be applied to all people with dyslexia, and warns that there may be other factors that account for dyslexia.

"We don't want to be thinking of developing diagnostic tests; we want to be thinking about detecting any of a whole range of problems a child might have during the learning process. Dyslexia is a heterogenous disorder and it's extremely unlikely you have a solution for every child."